I. Field of the Invention
The present invention relates to position location. More particularly, the present invention relates to a novel and improved method and apparatus for performing position location in wireless communications system.
II. Description of the Related Art
Both government regulation and consumer demand have driven the demand for position location functionality in cellular telephones. The global positioning system (GPS) is currently available for performing position location using a GPS receiver in conjunction with a set of earth orbiting satellites. It is therefore desirable to introduce GPS functionality into a cellular telephone.
Cellular telephones, however, are extremely sensitive to cost, weight and power consumption considerations. Thus, simply adding additional circuitry for performing GPS location is an unsatisfactory solution for providing position location functionality in a cellular telephone. Thus, the present invention is directed to providing GPS functionality in a cellular telephone system with a minimum of additional hardware, cost and power consumption.
The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the correction signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.